/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
/*  SHA-1 implementation in JavaScript | (c) Chris Veness 2002-2010 | www.movable-type.co.uk      */
/*   - see http://csrc.nist.gov/groups/ST/toolkit/secure_hashing.html                             */
/*         http://csrc.nist.gov/groups/ST/toolkit/examples.html                                   */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */

// Adapted for use in Qooxdoo by Daniel Swann 20/06/2012

qx.Class.define("custom.Sha1",
{
  extend : qx.core.Object,

  construct : function()
  {
  },

  members :
  {
      
    /**
     * Generates SHA-1 hash of string
     *
     * @param {String} msg                String to be hashed
     * @param {Boolean} [utf8encode=true] Encode msg as UTF-8 before generating hash
     * @returns {String}                  Hash of msg as hex character string
     */
    hash : function(msg, utf8encode) 
    {
      utf8encode =  (typeof utf8encode == 'undefined') ? true : utf8encode;
      
      // convert string to UTF-8, as SHA only deals with byte-streams
      if (utf8encode) msg = this.encode(msg);
      
      // constants [§4.2.1]
      var K = [0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6];
      
      // PREPROCESSING 
      
      msg += String.fromCharCode(0x80);  // add trailing '1' bit (+ 0's padding) to string [§5.1.1]
      
      // convert string msg into 512-bit/16-integer blocks arrays of ints [§5.2.1]
      var l = msg.length/4 + 2;  // length (in 32-bit integers) of msg + ‘1’ + appended length
      var N = Math.ceil(l/16);   // number of 16-integer-blocks required to hold 'l' ints
      var M = new Array(N);
      
      for (var i=0; i<N; i++) {
        M[i] = new Array(16);
        for (var j=0; j<16; j++) {  // encode 4 chars per integer, big-endian encoding
          M[i][j] = (msg.charCodeAt(i*64+j*4)<<24) | (msg.charCodeAt(i*64+j*4+1)<<16) | 
            (msg.charCodeAt(i*64+j*4+2)<<8) | (msg.charCodeAt(i*64+j*4+3));
        } // note running off the end of msg is ok 'cos bitwise ops on NaN return 0
      }
      // add length (in bits) into final pair of 32-bit integers (big-endian) [§5.1.1]
      // note: most significant word would be (len-1)*8 >>> 32, but since JS converts
      // bitwise-op args to 32 bits, we need to simulate this by arithmetic operators
      M[N-1][14] = ((msg.length-1)*8) / Math.pow(2, 32); M[N-1][14] = Math.floor(M[N-1][14])
      M[N-1][15] = ((msg.length-1)*8) & 0xffffffff;
      
      // set initial hash value [§5.3.1]
      var H0 = 0x67452301;
      var H1 = 0xefcdab89;
      var H2 = 0x98badcfe;
      var H3 = 0x10325476;
      var H4 = 0xc3d2e1f0;
      
      // HASH COMPUTATION [§6.1.2]
      
      var W = new Array(80); var a, b, c, d, e;
      for (var i=0; i<N; i++) {
      
        // 1 - prepare message schedule 'W'
        for (var t=0;  t<16; t++) W[t] = M[i][t];
        for (var t=16; t<80; t++) W[t] = this.ROTL(W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16], 1);
        
        // 2 - initialise five working variables a, b, c, d, e with previous hash value
        a = H0; b = H1; c = H2; d = H3; e = H4;
        
        // 3 - main loop
        for (var t=0; t<80; t++) {
          var s = Math.floor(t/20); // seq for blocks of 'f' functions and 'K' constants
          var T = (this.ROTL(a,5) + this.f(s,b,c,d) + e + K[s] + W[t]) & 0xffffffff;
          e = d;
          d = c;
          c = this.ROTL(b, 30);
          b = a;
          a = T;
        }
        
        // 4 - compute the new intermediate hash value
        H0 = (H0+a) & 0xffffffff;  // note 'addition modulo 2^32'
        H1 = (H1+b) & 0xffffffff; 
        H2 = (H2+c) & 0xffffffff; 
        H3 = (H3+d) & 0xffffffff; 
        H4 = (H4+e) & 0xffffffff;
      }

      return this.toHexStr(H0) + this.toHexStr(H1) + 
        this.toHexStr(H2) + this.toHexStr(H3) + this.toHexStr(H4);
    },

    //
    // function 'f' [§4.1.1]
    //
    f : function(s, x, y, z)  
    {
      switch (s) {
      case 0: return (x & y) ^ (~x & z);           // Ch()
      case 1: return x ^ y ^ z;                    // Parity()
      case 2: return (x & y) ^ (x & z) ^ (y & z);  // Maj()
      case 3: return x ^ y ^ z;                    // Parity()
      }
    },

    //
    // rotate left (circular left shift) value x by n positions [§3.2.5]
    //
    ROTL : function(x, n) 
    {
      return (x<<n) | (x>>>(32-n));
    },

    //
    // hexadecimal representation of a number 
    //   (note toString(16) is implementation-dependant, and  
    //   in IE returns signed numbers when used on full words)
    //
    toHexStr : function(n) 
    {
      var s="", v;
      for (var i=7; i>=0; i--) { v = (n>>>(i*4)) & 0xf; s += v.toString(16); }
      return s;
    },


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
/*  Utf8 class: encode / decode between multi-byte Unicode characters and UTF-8 multiple          */
/*              single-byte character encoding (c) Chris Veness 2002-2010                         */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */


    /**
     * Encode multi-byte Unicode string into utf-8 multiple single-byte characters 
     * (BMP / basic multilingual plane only)
     *
     * Chars in range U+0080 - U+07FF are encoded in 2 chars, U+0800 - U+FFFF in 3 chars
     *
     * @param {String} strUni Unicode string to be encoded as UTF-8
     * @returns {String} encoded string
     */
    encode : function(strUni) 
    {
      // use regular expressions & String.replace callback function for better efficiency 
      // than procedural approaches
      var strUtf = strUni.replace(
          /[\u0080-\u07ff]/g,  // U+0080 - U+07FF => 2 bytes 110yyyyy, 10zzzzzz
          function(c) { 
            var cc = c.charCodeAt(0);
            return String.fromCharCode(0xc0 | cc>>6, 0x80 | cc&0x3f); }
        );
      strUtf = strUtf.replace(
          /[\u0800-\uffff]/g,  // U+0800 - U+FFFF => 3 bytes 1110xxxx, 10yyyyyy, 10zzzzzz
          function(c) { 
            var cc = c.charCodeAt(0); 
            return String.fromCharCode(0xe0 | cc>>12, 0x80 | cc>>6&0x3F, 0x80 | cc&0x3f); }
        );
      return strUtf;
    },

    /**
     * Decode utf-8 encoded string back into multi-byte Unicode characters
     *
     * @param {String} strUtf UTF-8 string to be decoded back to Unicode
     * @returns {String} decoded string
     */
    decode : function(strUtf) 
    {
      // note: decode 3-byte chars first as decoded 2-byte strings could appear to be 3-byte char!
      var strUni = strUtf.replace(
          /[\u00e0-\u00ef][\u0080-\u00bf][\u0080-\u00bf]/g,  // 3-byte chars
          function(c) {  // (note parentheses for precence)
            var cc = ((c.charCodeAt(0)&0x0f)<<12) | ((c.charCodeAt(1)&0x3f)<<6) | ( c.charCodeAt(2)&0x3f); 
            return String.fromCharCode(cc); }
        );
      strUni = strUni.replace(
          /[\u00c0-\u00df][\u0080-\u00bf]/g,                 // 2-byte chars
          function(c) {  // (note parentheses for precence)
            var cc = (c.charCodeAt(0)&0x1f)<<6 | c.charCodeAt(1)&0x3f;
            return String.fromCharCode(cc); }
        );
      return strUni;
    }
  }
});

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
